She was taken to North Manchester General Hospital where her condition was today described as critical.

Her family are at her bedside.

An independent investigation has been launched by the Police Complaints Commission.

The fully-liveried police van was responding to an emergency 999 call to a domestic-related incident when it was involved in the accident at around 11.10pm on Saturday.

It was travelling south towards Manchester at the time, with its blue lights on and its siren activated.

The woman was struck as she crossed the road with a friend, who was not hurt.

Investigation

The van collided with a parked car after the collision.

Police today said early indications suggest that the woman had run out into the path of the van from a nearby pub.

Her friend raised the alarm using a mobile phone.

Police sealed off the section of road for more than an hour as an investigation began.

Police were today studying footage of the collision captured on council-owned security cameras. The driver passed a routine breath test.

A police spokesman said: "The fully signed van was responding to an emergency call with its lights and siren on.

"The woman was taken to North Manchester General Hospital where she remains in a critical condition today. The incident has now been referred to the independent Police Complaints Commission for investigation."

Witnesses to the accident were today urged to call traffic offices on 0161 856 3572 or Crimestoppers on 0800 555 111.